A semiconductor device structure can include: (i) a first semiconductor layer having dopants of a first type; (ii) a second semiconductor layer having the dopants of the first type on the first semiconductor layer, where the second semiconductor layer is lightly-doped relative to the first semiconductor layer; (iii) first and second column regions spaced from each other in the second semiconductor layer, where the second column region is arranged between two of the first column regions; and (iv) first and second first sub-column regions laterally arranged in the second column region, where a doping concentration of the first sub-column region decreases in a direction from the first column region to the second sub-column region, and where a doping concentration of the second sub-column region decreases in a direction from the first column region to the first sub-column region.